The wagon measures 60" x 31.5". The maximum weight including the weight of the wagon would never be over 600 lbs. I am more interested in torque than speed. Maximum speed 5 mph (walking speed on the beach). The wagon has a solid 3/4" rear axle with 18" diameter tires that are 8.5 inches wide. The maximum run time needs to be about 2 hrs. I would prefer a thumb throttle. and keyed on off switch. I am working on a limited budget, but want enough power to get the job done. What would you recommend.
I would also like to get an idea of the price difference to have the option to go in reverse.
Figuring out what size batteries would provide a two hour run time will have to be an educated guess and not a calculation based on a formula because there are so many variables involved such as the percent of time and steepness of inclines the wagon goes up, if the wagon is driven in wet hard sand or dry soft sand, amount of time the wagon is driven on paved areas, dirt trails, and sand, etc. Assuming the the wagon will be primarily driven on relatively hard wet sand then my best guess is that three 12 Volt 35 Ah batteries will provide a minimum two hour run time. Of course if this size battery pack does not provide enough run time then an additional three identical batteries could be added to the battery pack which would double its run time.
We just got in a box of large high power reversing switches that could be used for reverse which cost $24.95.
The batteries and charger are going to be the most expensive parts of the project. 12 Volt 35Ah batteries cost around $80 each and three are needed for a 36 Volt battery pack so that would be $240.00. They would require a 36 Volt 4.5 Amp or larger battery charger which costs around $160.00. The motor is $149.95, controller $49.95, throttle $19.95, key switch $11.95, charger port $5.95. There would also be some wire and connectors that would be needed for the project.
All together the price of these parts without the reverse switch would be around $600.00 not including the axle adapter and sprocket or chain. If you would like I could make a kit out of these parts and apply a discount to the kit to help bring the cost down a little. If you are interested in a kit please let me know if you: Want it with a reverse switch? Want it with the axle adapter (if so let me know for 3/4" or 1" axle), 50 tooth chain sprocket, and chain?
I need to keep the cost down.
I will not need batteries , I have heavy duty gel cell deep cycle batteries on hand.
I do not need charger or charging port.
I can also weld a sleeve on the axle to make it 1" where the sprocket attaches without changing anything.
Would the MOT-24450G 24 Volt 450 Watt gear motor do the same job ? On another power wagon build I read
" there is no power advantage to using a 36 Volt 450 Watt motor over a 24 Volt 450 Watt motor, they both have the exact same amount of power, torque, and RPM."
Will the 24V system do the job? If not, just let me know.
If a 24V system will do the job. I would need the price of a kit to include 24V motor, 24V controller, throttle, key switch, reverse switch, 50 tooth chain sprocket for 1" axle, and chain.
If a 36V system is absolutely necessary, I need the price of a kit for 36V system to include the same items.
The MOT-24450G 24 Volt 450 Watt gear motor has the same power and torque as the 36 Volt 450 Watt gear motor. Even though they are close in Watts rating the 450 Watt gear motors are much smaller than the 36 Volt 600 Watt gear motor so they can not handle as much of a load for as long of a time without overheating. I think that with a 600 pound load it would be okay to use a 24 Volt 450 Watt gear motor if the top speed was closer to 3 MPH instead of 5 MPH.
I did some calculations for the 450 Watt gear motor.
The 450 Watt gear motors have a 9 tooth sprocket for 1/2" x 1/8" (#410) bicycle chain. I currently do not know where to order sprockets for #410 chain that are larger than 60 teeth. #410 sprockets over 60 teeth might be available though so you may want to research to see if you can find them.
I can make the kit with the 24 Volt 450 Watt gear motor without the chain sprocket and axle adapter if you would like?
The 600 lb. maximum and 2hr run time are over kill figures.
How about a 24V 450W kit with the largest sprocket you have available (between 50-60 teeth) for a 1" shaft with chain.
We need to have a machine shop custom make the 3/4" axle hub so there will be a 3-4 business day delay before we will be able to ship the kit out.
To keep the price down I did not add a motor bracket to the kit but if you would like a motor bracket it can be added to the order. Here is a link to item # HDW-250 motor bracket which fits the 24 Volt 450 Watt gear motor. https://cart.electricscooterparts.com/250w/450w-gear-motor-bracket-with-mounting-hardware-for-electric-bicycles
If you have any questions or need any changes made to the kit please let me know.
Here is the top speed and gear ratio calculation for KIT-135 using with 18" wheels:
The top speed is 6.04 MPH. The MOT-24450G gear motor is commonly used on electric bicycles which weight between 200-250 pounds including their rider and are geared to go 15 MPH. So with 6.04 MPH gearing this motor should be able to handle a lot of weight without any problem.